Blue skies, a late summer day with hints of fall: The weather in New York and Washington today felt eerily similar to September 11, 2001.

CORNISH: At ground zero in New York City, in Shanksville, Pennsylvania, and at the Pentagon here in Washington, people stood quietly today under those blue skies and remembered the dead. And the presidential campaign was also quieter. As NPR's Mara Liasson reports, the candidates took a break from their most fierce partisan battles.

(SOUNDBITE OF TAPS)

MARA LIASSON, BYLINE: A Marine bugler played taps at the White House as the president and first lady observed a moment of silence. Later, Mr. Obama spoke at a memorial service at the Pentagon.

PRESIDENT BARACK OBAMA: Most of the Americans we lost that day had never considered the possibility that a small band of terrorists halfway around the world could do us such harm. Most had never heard the name al-Qaida. And yet it's because of their sacrifice that we've come together and dealt a crippling blow to the organization that brought evil to our shores.

LIASSON: Both the Obama and Romney campaigns said they pulled all their political ads today in observance of the September 11th anniversary. But politics wasn't very far offstage. The Obama campaign sees foreign policy as an advantage this year. During their convention, speaker after speaker reminded voters about the meticulous attention the Obamas have paid to returning vets and their families, how the president ended the war in Iraq and is now winding down the war in Afghanistan. And just in case you forgot...

(SOUNDBITE OF DEMOCRATIC NATIONAL CONVENTION)

SENATOR JOHN KERRY: Ask Osama bin Laden if he is better off now than he was four years ago.

LIASSON: Romney gave the Obama team an opening when, in his convention speech, he failed to mention the troops or utter the word Afghanistan. He had to explain himself on Fox News.

(SOUNDBITE OF TV INTERVIEW)

MITT ROMNEY: When you give a speech, you don't go through a laundry list. You talk about the things that you think are important, and I described in my speech my commitment to a strong military unlike the president's decision to cut our military. And I didn't use the word troops. I used the word military. I think they refer to the same thing.

LIASSON: But that wasn't good enough for the Obama campaign. Retired Army General and Obama surrogate Wesley Clark continued to bash Romney in a conference call yesterday.

GENERAL WESLEY CLARK: Mitt Romney's failure to mention Afghanistan, it's more than an omission. It reveals a severe lack of understanding about the job as president. Frankly, it's just unbecoming of someone who wants to become commander in chief.

LIASSON: Romney still enjoys the Republicans' traditional advantage among voters who are veterans, but the Obama campaign is confident it can chip away at that. Why? Because, says Dan Drezner, professor of international politics at Tufts University, this year, for the first time in 40 years of presidential campaign polling, voters trust the Democrat more than the Republican on national security. And, Drezner says, Romney's credentials have slipped since the primaries when he did not have to debate anyone with serious foreign policy credentials.

DR. DANIEL DREZNER: Since then, Romney has gone on a trip overseas in July that I think could best be described as not going terribly well. And then he went to the Republican National Convention, and for the first time since 1952, a Republican nominee failed to mention anything with respect to the war.

LIASSON: And there's the actual policy debate before the broader electorate. Romney is promising to increase military spending and to be more confrontational with Iran and China. Drezner says a new poll, released by the Chicago Council of Global Affairs, suggests that stance may not sell.

DREZNER: If you look at those poll results, that's pretty much the opposite consensus of what most Americans want. And independent voters want an even lower American profile overseas than either Republicans or Democrats, and also millennials, sort of young voters, which also increasingly want to have the United States focus much more on repairing its economy at home rather than focusing overseas.

LIASSON: National security isn't anywhere near the top of the list of issues for voters this year, but it is an important consideration as Americans choose a commander in chief. So this argument will continue. On October 22nd, the third and final presidential debate will be devoted solely to foreign policy. Mara Liasson, NPR News, the White House. Transcript provided by NPR, Copyright NPR.